In recent years the use of perms, hair coloring, bleaching, and so on has become popular. On the other hand, hair damage accompanying these chemical treatments has become a problem. Conventionally, a hair cosmetic such as a rinse, a conditioner or a treatment is used in order to improve the feel of hair after shampooing, and further improvement of performance has been desired from the viewpoint of alleviating hair damage.
Patent Document 1 proposes a hair cosmetic containing a specific branched fatty acid as a technique for repairing or suppressing hair damage and providing good texture.
Patent Documents 2 and 5 disclose hair cosmetics that repair or suppress hair damage and fatigue failure due to chemical treatments, drying with a dryer and daily hair care activity, and can provide desirable softness and a supple feel from moistening to drying. These hair cosmetics contain a specific tertiary amine or a salt thereof, a specific aromatic alcohol, a specific branched fatty acid or a salt thereof and water. It is stated that as a result these hair cosmetics are excellent in terms of softness, smoothness, moist feel, suppleness, and the like after application to hair and drying.
Furthermore, Patent Document 3 discloses a lipid dispersion composition for the purpose of efficiently repairing hair damage, and a hair cosmetic containing the same. The lipid dispersion composition of Patent Document 3 is produced by dispersing a di-long chain alkyl quaternary ammonium salt type cationic surfactant, a sterol, and a quaternary ammonium salt type cationic surfactant having a branched fatty acid amide structure in a dispersion medium containing 50 wt % or more of a polyol.
Furthermore, Patent Document 4 discloses a hair treatment composition containing cholesterol, a basic amino acid, a fatty acid, and a multilamellar vesicle dispersion that is stabilized by a nonionic surfactant, and a hair treatment composition such as a shampoo or a conditioner containing multilamellar vesicle dispersion, for the purpose of repairing and preventing hair damage. It is stated that this treatment composition specifically promotes penetration of some hair-treatment effective materials into hair fibers.
As one method for producing an emulsion composition, a phase inversion emulsification method or a liquid crystal emulsification method is known. The phase inversion emulsification method is a method in which emulsification is carried out while adding an aqueous phase to an oil phase. The liquid crystal emulsification method is a method in which emulsification is carried out while adding an aqueous phase to a liquid crystal phase. For example, in Non-Patent Document 1, a fine emulsion having an average particle size of no more than 1 μm is formed by utilizing a great reduction in the oil/water interfacial tension near the phase inversion point when carrying out emulsification while adding an aqueous phase to an oil phase.